This invention relates to an instrument for applying a surgical clip in body tissue, and more particularly to an instrument for applying a surgical clip for anastomoses of a blood vessel.
The term "anastomosis" covers a variety of procedures in which blood vessels or other tubular members, such as parts of the colon, are joined or reconnected. Vessels may be joined in a variety of relative orientations, including end-to-end and end-to-side. Solid tubular structures such as peripheral nerves can also be joined together, as well as solid structures such as subcutaneous tissue and skin.
Anastomoses are performed by joining, clipping or suturing the vessels together at the juncture between them. When surgical clips are used, vascular anastomosis is achieved by approximating a pair of vessels, partially everting them and then joining the vessels by placing the arms of the surgical clip over the adjoined vessels. The arms of the surgical clip are then crimped about the tissue in such a way as to hold the vessel ends together without penetrating them.
Alternatives to conventional suturing process of joining vessels have been developed in order to prevent thrombosis which tends to occur at the points of penetration of the sutures. One such alternative, particularly for larger vessels, involves mechanical connectors such as collars. A second alternative to suturing is the use of surgical clips which are applied along the vessel juncture to perform a holding function similar to that of sutures, but without penetrating the vessel walls. Two such nonpenetrating clips are shown in U.S. Pat. Nos. 4,586,503 and 4,733,664 to Kirsch et al. The former patent discloses a surgical microclip formed of plastically deformable metal or plastic material having minimal spring-back when crimped. The clip has a pair of parallel curved legs joined by a bridge at one end and terminating in rounded tips at the other end. The clip grips the edges of adjacent and everted tissue by crimping the legs together. The latter patent discloses a vascular surgical clip comprising a plastically deformable body portion, a tang for deforming the body, and a neck connecting the tang to the body, wherein the neck is designed to break upon application of a predetermined tensile force to the tang, and the body is designed to deform upon application to the tang of less than the predetermined tensile force.
As described in the above patents, the non-penetrating clips are applied over opposed edges of the vessels, the edges first being everted, or turned outward, to form flanges that are gripped between the jaws of the clips. Eversion not only enables the clip jaws to better grip the vessels, but also insures that only the interior surfaces of the vessels are in contact.
Vascular microsurgical clips are typically applied with a small hand-held tool that enables the surgeon to precisely place the clip over the tissue edges, and then to dose the clip, as by applying a squeezing pressure to the tool. One example of a prior art clip applier for use in vascular microsurgery is disclosed in both U.S. Pat. Nos. 4,733,664 and 4,929,240 to Kirsch et al. These patents disclose a tool for applying a surgical clip, the tool including means for gripping and applying tension to the tang of the clip while also having means for simultaneously pushing against shoulders on the clip body. The tool disclosed in these patents requires that a clip be reloaded into the clip applier after each clip is fixed.
The need exists for an improved surgical clip and particularly for an instrument for applying such a surgical clip which can be utilized for vascular anastomosis. One specific need is for an instrument that can hold a plurality of clips and automatically feed and apply the clips individually to the vessel. It would also be desirable for the instrument to be simple to manufacture, easy to manipulate and which applies the clips with consistent accuracy so as to provide a secure joining of vessels and tissue. Since the instrument is intended to apply clips during vascular anastomosis it would be desirable to configure it similarly to other vascular surgical devices, i.e. tweezers or pincerlike implements, which are held between the thumb and forefinger of the user. One advantage of such a pincerlike implement is that it enables the user to activate the instrument near the working distal end, thereby providing improved tactility and stability.